Anyone who’s seen the aquatic ballet of schooling fish knows that nature provides glorious examples of synchrony–the rhythmic interplay of parts that unconsciously combine in patterns to make up a greater whole. But advanced computing and sophisticated math have shown recently that sync also underlies some of the most complex and perplexing phenomena around–from fads and traffic to human consciousness. Sync is embedded in the rules of nature, rules we’ve never been able to figure out with crude calculation and observation alone–even though we’ve been surrounded by them all along. “The entire universe may carry the seeds of its own order,” says Strogatz, a professor of applied math at Cornell. “This is the future of science–the way to answer the big, eternal questions.” And the small ones.
FIREFLIES
How, for instance, do some groups of fireflies manage to flash together in rhythm, as if driven by a drumbeat inaudible to the rest of the world? For years only the lucky people who saw the spectacle believed in it. “It just seemed contrary to all the laws of nature,” says Strogatz. In fact, the phenomenon illustrated them perfectly. Firefly brains are equipped with a metronome that sets the pace of their flashes based on what other fireflies are doing. If by chance a few insects flash in unison, others will notice and adjust their own flashes to match, until the entire group is putting on a coordinated light show with no leader to set the tempo. Only males synchronize, mainly in areas with thick vegetation, from Tennessee to Thailand. The group may be acting in concert to attract females who can’t see single bugs through the brush.
FISH
Fish, too, use sync as a survival strategy. It’s long been known that schooling reduces an individual fish’s chances of being eaten. Last month biologists announced in Nature that sync helps the same fish find something to eat. The goatfish of the Red Sea swim in groups of a dozen. At mealtime, the entire school drops to the seafloor to root for food. If a worm or shellfish manages to escape one hungry mouth, the hapless creature will be pushed over to the next one. Group foraging is so ingrained in goatfish that individuals kept in separate (but adjacent) tanks will synchronize their movements even if they have never hunted.
WOMEN
It’s less clear why a certain, more familiar organism might demonstrate sync. Nonetheless, the old wives’ tales about female co-workers with coinciding menstrual periods appear to be true. Women chemically “communicate” the timing of their cycles via pheromones. Their bodies may adjust to the pace of those around them. “Many male scientists don’t think this is real,” says Strogatz. It took a female undergraduate, Martha McClintock, to prove it by surveying her classmates at Wellesley. There’s also the case of biologist Genevieve Switz, a “strong synchronizer.” In tests, women living miles away from her were exposed to her sweat. After several months, their periods started within 3.4 days of hers.
TRAFFIC
The last place you’d expect to find sync would be on the highway. But “traffic physicists” have noticed that despite their tendency to tailgate and cut off other drivers, motorists usually avoid traffic jams simply by acting in sync. In computer simulations, cars and trucks spontaneously synchronize, traveling as a solid block of vehicles–as long as there aren’t too many of them. Even a few extra cars can tip the system into chaos, a phenomenon well known to rush-hour drivers.
NEURONS
If the brain is an orchestra, each neuron plays a different instrument. With no conductor, how does the brain make sense of the racket? It may use sync. Recognizing a face, for example, requires neurons to put together a huge amount of data. A familiar face may cause 80 percent of the neurons involved to fire in unison. If 90 percent join in, it’s even more likely the face will be recognized. All consciousness may in fact be a result of synchronized neuron-firing. Strogatz notes that scientists have picked up a 40-cycle-per-second rhythm in the brain. No one really knows what it means–yet.
FADS
If scientists could say why fads like the Pet Rock and the Rubik’s Cube take off, they’d do a service indeed. They suspect sync is involved; how else could millions of people end up doing the same thing without being told to? Alas, despite copious research into social networks, the stranger aspects of human behavior are still a mystery. But as Strogatz notes, “We do pay more attention to others than to our own common sense.” In other words, we may all be a little like fireflies. It is, you have to admit, an enlightening thought.
